I think we shouldn't down play things happening here...but...
It should be recognized that these violent incidences have the 'hive mind' type reactions, where a few miscreants that fit the bill for misogynistic ass wipes, create a swarm of trolls that cause the enormous damage. The same is happening in ferguson, as you have a situation that attracts the malcontents whose only real desire it to cause pain, suffering and whatever.
I only say this because of what the mind believes about the preponderance of people that would do this kind of activity in solitude versus those who would only act, or do act, in congregations.
We had the discussion on boingboing recently about how certain beliefs in society, such as, 'binge drinking is acceptable' are generally held by a minority, but propped up by a majority of thinkers, who think to go against the norm in a given situation would put them at a disadvantage. The group think is what is important to recognize.
So at the end of the day, every time this minority acts, there's a majority which doesn't push back, allowing them to appear grander than they are.
If we don't recognize that there's a seed of mysogny, surrounded by a coating of trolls, given space by an apathy, we may realize and create the inverse avenue, and create the vaccuum of space that allows hate itself to breed, regardless of idealogues, because the trolls will flutter to either side.